/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated January 1, 2020. Replaces all prior versions.
 *
 * Copyright (c) 2013-2020, Esoteric Software LLC
 *
 * Integration of the Spine Runtimes into software or otherwise creating
 * derivative works of the Spine Runtimes is permitted under the terms and
 * conditions of Section 2 of the Spine Editor License Agreement:
 * http://esotericsoftware.com/spine-editor-license
 *
 * Otherwise, it is permitted to integrate the Spine Runtimes into software
 * or otherwise create derivative works of the Spine Runtimes (collectively,
 * "Products"), provided that each user of the Products must obtain their own
 * Spine Editor license and redistribution of the Products in any form must
 * include this license and copyright notice.
 *
 * THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
 * BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 *****************************************************************************/

package com.esotericsoftware.spine;

import java.util.ArrayList;
import org.joml.Vector2f;
import static com.esotericsoftware.spine.utils.SpineUtils.PI;
import static com.esotericsoftware.spine.utils.SpineUtils.PI2;
import static com.esotericsoftware.spine.utils.SpineUtils.atan2;
import static com.esotericsoftware.spine.utils.SpineUtils.cos;
import static com.esotericsoftware.spine.utils.SpineUtils.degRad;
import static com.esotericsoftware.spine.utils.SpineUtils.sin;

/** Stores the current pose for a transform constraint. A transform constraint adjusts the world transform of the
 * constrained
 * bones to match that of the target bone.
 * <p>
 * See <a href="http://esotericsoftware.com/spine-transform-constraints">Transform constraints</a>
 * in the Spine User Guide. */
public class TransformConstraint implements Updatable {
    final TransformConstraintData data;
    final ArrayList<Bone> bones;
    Bone target;
    float rotateMix, translateMix, scaleMix, shearMix;

    boolean active;
    final Vector2f temp = new Vector2f();

    public TransformConstraint(TransformConstraintData data, Skeleton skeleton) {
        if (data == null) {
            throw new IllegalArgumentException("data cannot be null.");
        }
        if (skeleton == null) {
            throw new IllegalArgumentException("skeleton cannot be null.");
        }
        this.data = data;
        rotateMix = data.rotateMix;
        translateMix = data.translateMix;
        scaleMix = data.scaleMix;
        shearMix = data.shearMix;
        bones = new ArrayList<>(data.bones.size());
        for (BoneData boneData : data.bones) {
            bones.add(skeleton.findBone(boneData.name));
        }
        target = skeleton.findBone(data.target.name);
    }

    /** Copy constructor. */
    public TransformConstraint(TransformConstraint constraint, Skeleton skeleton) {
        if (constraint == null) {
            throw new IllegalArgumentException("constraint cannot be null.");
        }
        if (skeleton == null) {
            throw new IllegalArgumentException("skeleton cannot be null.");
        }
        data = constraint.data;
        bones = new ArrayList<>(constraint.bones.size());
        for (Bone bone : constraint.bones) {
            bones.add(skeleton.bones.get(bone.data.index));
        }
        target = skeleton.bones.get(constraint.target.data.index);
        rotateMix = constraint.rotateMix;
        translateMix = constraint.translateMix;
        scaleMix = constraint.scaleMix;
        shearMix = constraint.shearMix;
    }

    /** Applies the constraint to the constrained bones. */
    public void apply() {
        update();
    }

    @Override
    public void update() {
        if (data.local) {
            if (data.relative) {
                applyRelativeLocal();
            } else {
                applyAbsoluteLocal();
            }
        } else {
            if (data.relative) {
                applyRelativeWorld();
            } else {
                applyAbsoluteWorld();
            }
        }
    }

    private void applyAbsoluteWorld() {
        float rotateMix = this.rotateMix, translateMix = this.translateMix, scaleMix = this.scaleMix, shearMix =
                this.shearMix;
        Bone target = this.target;
        float ta = target.a, tb = target.b, tc = target.c, td = target.d;
        float degRadReflect = ta * td - tb * tc > 0 ? degRad : -degRad;
        float offsetRotation = data.offsetRotation * degRadReflect, offsetShearY = data.offsetShearY * degRadReflect;
        ArrayList<Bone> bones = this.bones;
        for (int i = 0, n = bones.size(); i < n; i++) {
            Bone bone = bones.get(i);
            boolean modified = false;

            if (rotateMix != 0) {
                float a = bone.a, b = bone.b, c = bone.c, d = bone.d;
                float r = atan2(tc, ta) - atan2(c, a) + offsetRotation;
                if (r > PI) {
                    r -= PI2;
                } else if (r < -PI) {
                    r += PI2;
                }
                r *= rotateMix;
                float cos = cos(r), sin = sin(r);
                bone.a = cos * a - sin * c;
                bone.b = cos * b - sin * d;
                bone.c = sin * a + cos * c;
                bone.d = sin * b + cos * d;
                modified = true;
            }

            if (translateMix != 0) {
                Vector2f temp = this.temp;
                target.localToWorld(temp.set(data.offsetX, data.offsetY));
                bone.worldX += (temp.x - bone.worldX) * translateMix;
                bone.worldY += (temp.y - bone.worldY) * translateMix;
                modified = true;
            }

            if (scaleMix > 0) {
                float s = (float) Math.sqrt(bone.a * bone.a + bone.c * bone.c);
                if (s != 0) {
                    s = (s + ((float) Math.sqrt(ta * ta + tc * tc) - s + data.offsetScaleX) * scaleMix) / s;
                }
                bone.a *= s;
                bone.c *= s;
                s = (float) Math.sqrt(bone.b * bone.b + bone.d * bone.d);
                if (s != 0) {
                    s = (s + ((float) Math.sqrt(tb * tb + td * td) - s + data.offsetScaleY) * scaleMix) / s;
                }
                bone.b *= s;
                bone.d *= s;
                modified = true;
            }

            if (shearMix > 0) {
                float b = bone.b, d = bone.d;
                float by = atan2(d, b);
                float r = atan2(td, tb) - atan2(tc, ta) - (by - atan2(bone.c, bone.a));
                if (r > PI) {
                    r -= PI2;
                } else if (r < -PI) {
                    r += PI2;
                }
                r = by + (r + offsetShearY) * shearMix;
                float s = (float) Math.sqrt(b * b + d * d);
                bone.b = cos(r) * s;
                bone.d = sin(r) * s;
                modified = true;
            }

            if (modified) {
                bone.appliedValid = false;
            }
        }
    }

    private void applyRelativeWorld() {
        float rotateMix = this.rotateMix, translateMix = this.translateMix, scaleMix = this.scaleMix, shearMix =
                this.shearMix;
        Bone target = this.target;
        float ta = target.a, tb = target.b, tc = target.c, td = target.d;
        float degRadReflect = ta * td - tb * tc > 0 ? degRad : -degRad;
        float offsetRotation = data.offsetRotation * degRadReflect, offsetShearY = data.offsetShearY * degRadReflect;
        ArrayList<Bone> bones = this.bones;
        for (int i = 0, n = bones.size(); i < n; i++) {
            Bone bone = bones.get(i);
            boolean modified = false;

            if (rotateMix != 0) {
                float a = bone.a, b = bone.b, c = bone.c, d = bone.d;
                float r = atan2(tc, ta) + offsetRotation;
                if (r > PI) {
                    r -= PI2;
                } else if (r < -PI) {
                    r += PI2;
                }
                r *= rotateMix;
                float cos = cos(r), sin = sin(r);
                bone.a = cos * a - sin * c;
                bone.b = cos * b - sin * d;
                bone.c = sin * a + cos * c;
                bone.d = sin * b + cos * d;
                modified = true;
            }

            if (translateMix != 0) {
                Vector2f temp = this.temp;
                target.localToWorld(temp.set(data.offsetX, data.offsetY));
                bone.worldX += temp.x * translateMix;
                bone.worldY += temp.y * translateMix;
                modified = true;
            }

            if (scaleMix > 0) {
                float s = ((float) Math.sqrt(ta * ta + tc * tc) - 1 + data.offsetScaleX) * scaleMix + 1;
                bone.a *= s;
                bone.c *= s;
                s = ((float) Math.sqrt(tb * tb + td * td) - 1 + data.offsetScaleY) * scaleMix + 1;
                bone.b *= s;
                bone.d *= s;
                modified = true;
            }

            if (shearMix > 0) {
                float r = atan2(td, tb) - atan2(tc, ta);
                if (r > PI) {
                    r -= PI2;
                } else if (r < -PI) {
                    r += PI2;
                }
                float b = bone.b, d = bone.d;
                r = atan2(d, b) + (r - PI / 2 + offsetShearY) * shearMix;
                float s = (float) Math.sqrt(b * b + d * d);
                bone.b = cos(r) * s;
                bone.d = sin(r) * s;
                modified = true;
            }

            if (modified) {
                bone.appliedValid = false;
            }
        }
    }

    private void applyAbsoluteLocal() {
        float rotateMix = this.rotateMix, translateMix = this.translateMix, scaleMix = this.scaleMix, shearMix =
                this.shearMix;
        Bone target = this.target;
        if (!target.appliedValid) {
            target.updateAppliedTransform();
        }
        ArrayList<Bone> bones = this.bones;
        for (int i = 0, n = bones.size(); i < n; i++) {
            Bone bone = bones.get(i);
            if (!bone.appliedValid) {
                bone.updateAppliedTransform();
            }

            float rotation = bone.arotation;
            if (rotateMix != 0) {
                float r = target.arotation - rotation + data.offsetRotation;
                r -= (16384 - (int) (16384.499999999996 - r / 360)) * 360;
                rotation += r * rotateMix;
            }

            float x = bone.ax, y = bone.ay;
            if (translateMix != 0) {
                x += (target.ax - x + data.offsetX) * translateMix;
                y += (target.ay - y + data.offsetY) * translateMix;
            }

            float scaleX = bone.ascaleX, scaleY = bone.ascaleY;
            if (scaleMix != 0) {
                if (scaleX != 0) {
                    scaleX = (scaleX + (target.ascaleX - scaleX + data.offsetScaleX) * scaleMix) / scaleX;
                }
                if (scaleY != 0) {
                    scaleY = (scaleY + (target.ascaleY - scaleY + data.offsetScaleY) * scaleMix) / scaleY;
                }
            }

            float shearY = bone.ashearY;
            if (shearMix != 0) {
                float r = target.ashearY - shearY + data.offsetShearY;
                r -= (16384 - (int) (16384.499999999996 - r / 360)) * 360;
                shearY += r * shearMix;
            }

            bone.updateWorldTransform(x, y, rotation, scaleX, scaleY, bone.ashearX, shearY);
        }
    }

    private void applyRelativeLocal() {
        float rotateMix = this.rotateMix, translateMix = this.translateMix, scaleMix = this.scaleMix, shearMix =
                this.shearMix;
        Bone target = this.target;
        if (!target.appliedValid) {
            target.updateAppliedTransform();
        }
        ArrayList<Bone> bones = this.bones;
        for (int i = 0, n = bones.size(); i < n; i++) {
            Bone bone = bones.get(i);
            if (!bone.appliedValid) {
                bone.updateAppliedTransform();
            }

            float rotation = bone.arotation;
            if (rotateMix != 0) {
                rotation += (target.arotation + data.offsetRotation) * rotateMix;
            }

            float x = bone.ax, y = bone.ay;
            if (translateMix != 0) {
                x += (target.ax + data.offsetX) * translateMix;
                y += (target.ay + data.offsetY) * translateMix;
            }

            float scaleX = bone.ascaleX, scaleY = bone.ascaleY;
            if (scaleMix != 0) {
                scaleX *= ((target.ascaleX - 1 + data.offsetScaleX) * scaleMix) + 1;
                scaleY *= ((target.ascaleY - 1 + data.offsetScaleY) * scaleMix) + 1;
            }

            float shearY = bone.ashearY;
            if (shearMix != 0) {
                shearY += (target.ashearY + data.offsetShearY) * shearMix;
            }

            bone.updateWorldTransform(x, y, rotation, scaleX, scaleY, bone.ashearX, shearY);
        }
    }

    /** The bones that will be modified by this transform constraint. */
    public ArrayList<Bone> getBones() {
        return bones;
    }

    /** The target bone whose world transform will be copied to the constrained bones. */
    public Bone getTarget() {
        return target;
    }

    public void setTarget(Bone target) {
        if (target == null) {
            throw new IllegalArgumentException("target cannot be null.");
        }
        this.target = target;
    }

    /** A percentage (0-1) that controls the mix between the constrained and unconstrained rotations. */
    public float getRotateMix() {
        return rotateMix;
    }

    public void setRotateMix(float rotateMix) {
        this.rotateMix = rotateMix;
    }

    /** A percentage (0-1) that controls the mix between the constrained and unconstrained translations. */
    public float getTranslateMix() {
        return translateMix;
    }

    public void setTranslateMix(float translateMix) {
        this.translateMix = translateMix;
    }

    /** A percentage (0-1) that controls the mix between the constrained and unconstrained scales. */
    public float getScaleMix() {
        return scaleMix;
    }

    public void setScaleMix(float scaleMix) {
        this.scaleMix = scaleMix;
    }

    /** A percentage (0-1) that controls the mix between the constrained and unconstrained scales. */
    public float getShearMix() {
        return shearMix;
    }

    public void setShearMix(float shearMix) {
        this.shearMix = shearMix;
    }

    @Override
    public boolean isActive() {
        return active;
    }

    /** The transform constraint's setup pose data. */
    public TransformConstraintData getData() {
        return data;
    }

    @Override
    public String toString() {
        return data.name;
    }
}
